Film formation mask, organic EL panel, and method of manufacturing the organic EL panel

ABSTRACT

In forming luminescent areas of organic EL devices of an organic EL display panel, it is necessary to prevent a display performance degradation in the vicinity of outermost edges of display area of the organic EL display panel. A film formation mask is used to form a film pattern of an organic layer containing a luminescent layer, in a manner such that the luminescent area formation sections can be covered. The film formation mask has a plurality of openings according to the film pattern, and false openings formed outside the area containing the openings but not useful in forming organic layer for forming luminescent areas. False openings are formed in positions corresponding to the outside of display area, and forms false patterns of an organic layer on the inner side of the adhesive area.

BACKGROUND OF THE INVENTION

The present invention relates to a film formation mask, an organic EL(Electroluminescent) panel formed by the film formation mask, and amethod of manufacturing the organic EL panel.

The present application claims priority from Japanese Application No.2003-74888, the disclosure of which is incorporated herein by reference.

An organic EL panel is produced by forming surface light emittingelements (based on luminescent areas of organic EL devices) on asubstrate, and forming a display area by arranging one or more surfacelight emitting elements. The luminescent areas are formed by providinglower electrodes of various structures on the substrate, and thenforming thereon a film pattern of an organic layer containing an organicluminescent layer, followed by forming thereon upper electrodes. Here,the film pattern is formed by using a film formation mask havingopenings corresponding to the film pattern, and accomplished by vapordeposition using the mask.

A process of forming an organic layer film pattern using the filmformation mask can be described as follows. Namely, luminescent areas oforganic EL devices are usually partitioned by an insulating film formedon the substrate. Then, the film formation mask having openings ofslightly larger width than luminescent areas is used to form an organiclayer film pattern on the luminescent areas. In particular, when aplurality of colors are to be displayed, it is required to use a filmformation mask having openings corresponding to a desired pattern ofdifferent luminescent colors. Thus, by changing or sliding the mask atan appropriate timing, it is possible to paint different colors on theorganic luminescent layer (Japanese Unexamined Patent ApplicationPublication No. 2002-367787).

Here, the organic layer includes an organic luminescent layer and otherlayers (an electroluminescent layer, a hole transporting layer, anelectron transporting layer, a hole injection layer, and an electroninjection layer). Although an organic layer is usually in a multi-layerstructure, it is also allowed to contain only single one layer which isan organic luminescent layer. Generally, even with a hole transportinglayer and an electron transporting layer or the like (each formed of asingle one kind of material and mounted on an identical substrate), itis allowed to use a film formation mask having different patternscorresponding to different luminescent colors in order to control filmthickness in each area of each luminescent color (Japanese UnexaminedPatent Application Publication No. 2001-237068).

To display a plurality of colors, there has been known not only theaforementioned method of painting different luminescent colors, but alsoCF Method and CCM Method in which an organic layer of a single colorsuch as white or blue is formed and a color conversion layer based on acolor filter or a fluorescent material is incorporated. Further, thereis Photobleaching Method in which an electromagnetic wave is applied toa specific area on an organic layer of a single color so as to realize amulti-color emission. At this time, although it is not necessary topaint different colors to cover each color, it is required to use a filmformation mask having a desired pattern in order to form an organiclayer of a specific pattern in a display area.

However, even when only single one color is displayed, it was stillrequired to use a film formation mask which has a predetermined pattern(usually, stripe-shaped pattern) corresponding to luminescent areas. Atthis time, in order to avoid a mask strength deterioration due to adense distribution of openings, an opening pitch (an interval betweenevery two adjacent openings) is enlarged, thereby forming an organiclayer film pattern in the display area of a display panel by dividing afilm formation process into several steps (Japanese Unexamined PatentApplication Publication No. 2000-48954).

In using a film formation mask for forming luminescent areas of organicEL devices on a substrate (i.e., when the mask is placed on thesubstrate), a tension is usually added to the perimeter of the mask toavoid the slacking of the mask, thereby keeping the entire mask in acompletely flat state. However, with the addition of the tension to theperimeter of the mask, distortion will occur in the outermost openingsof the film formation mask irrespective of the shape of these openings.Then, once film pattern is formed on the substrate through the deformedopenings, film pattern disorder will occur near the outmost edges of thedisplay area, resulting in deteriorated display performance near theoutermost edges of the display area. Consequently, it becomes impossibleto ensure an appropriate display in the entire display area.

Moreover, it is known that an organic layer of each organic EL devicewill be deteriorated due to an unavoidable contact with the surroundingatmospheric air, since moisture and oxygen existing in the surroundingatmospheric air can cause such deterioration. In order to prevent suchdeterioration, an entire display area of an organic EL panel is usuallycovered by an encapsulation member. In detail, an adhesive agent isapplied to the substrate outside the display area so as to form anadhesive-applied perimeter around the display area. Then, an annulararea along the perimeter of the encapsulation member is tightly bondedto the adhesive-applied area of the substrate, thereby protecting theentire display area of organic EL panel from the surrounding atmosphericair.

However, since an adhesive agent for use in the capsulation alsocontains moisture, oxygen or the like which can deteriorate the organiclayer, when such an adhesive agent get into contact with the organiclayer, the moisture and oxygen or the like will invade into the organiclayer and thus cause the organic layer to be deteriorated. Inparticular, if an amount of the adhesive agent applied is too large, theapplied adhesive agent will spread towards the display area once theencapsulation member is pressed onto the substrate, hence causing theadhesive agent to contact the outer edge of the display area. As aresult, the display performance will be deteriorated near the outermostedge of the display area, making it impossible to ensure an appropriatedisplay in the entire display area.

SUMMARY OF THE INVENTION

The present invention is to solve the above-discussed problems and anobject of the invention is that when luminescent areas of organic ELdevices are formed by using a film formation mask so as to form organiclayer film pattern on a substrate, it is possible to prevent displayperformance deterioration near the outermost edges of the display areaof an obtained display panel.

In one aspect of the present invention, there is provided a filmformation mask for forming an organic layer film pattern when organic ELdevices are to be formed on a substrate, each organic EL deviceincluding a pair of electrodes and an organic layer containing anorganic luminescent layer, the organic layer being interposed betweenthe pair of electrodes, characterized in that the film formation maskhas openings arranged corresponding to a film pattern for formingluminescent areas of the organic EL devices, and has false openings notfor use in forming the organic layer and located outside an areacontaining the openings.

In another aspect of the present invention, there is provided an organicEL panel including a substrate and organic EL devices formed on thesubstrate, each organic EL device including a pair of electrodes and anorganic layer containing an organic luminescent layer, the organic layerbeing interposed between the pair of electrodes, characterized in thatformed on the substrate are a film pattern of the organic layer forforming luminescent areas of the organic EL devices, and false patternsof the organic layer located outside an area containing the luminescentareas.

In a further aspect of the present invention, there is provided a methodof manufacturing an organic EL panel including a substrate and organicEL devices formed on the substrate, each organic EL device including apair of electrodes and an organic layer containing an organicluminescent layer, the organic layer being interposed between the pairof electrodes, characterized in that in a process of forming on thesubstrate a film pattern of the organic layer for forming luminescentareas of the organic EL devices, false patterns of the organic layer arealso formed on the substrate outside an area containing the luminescentareas.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention willbecome clear from the following description with reference to theaccompanying drawings, wherein:

FIG. 1 is an explanatory view showing a film formation mask according toan embodiment of the present invention;

FIG. 2 is a plan view showing the film formation mask of the presentinvention;

FIG. 3 is an explanatory view showing the film formation mask of thepresent invention, indicating the size of false openings;

FIG. 4 is an explanatory view showing an operation of the film formationmask of the present invention;

FIGS. 5A-5D are explanatory views showing a process of manufacturing anorganic EL panel using the film formation mask of the present invention;

FIG. 6 is a cross sectional view showing an organic EL panel formedaccording to an embodiment of the present invention, and indicating anarea near a base end thereof;

FIG. 7 is an explanatory view showing a method of manufacturing anorganic EL panel according to an embodiment of the present invention,and indicating an operation of the manufactured organic EL panel;

FIGS. 8A-8C are explanatory views showing several film formation masksformed according to another embodiment of the present invention;

FIG. 9 is an explanatory view showing an organic EL panel treated bypainting luminescent areas with different colors using a film formationmask formed according to another embodiment of the present invention;

FIGS. 10A-10C are explanatory views showing several different falsepatterns formed by different film formation masks according to anotherembodiment of the present invention;

FIGS. 11A and 11B are explanatory views showing a film formation maskaccording to another embodiment of the present invention;

FIGS. 12A-12C are explanatory views showing several different filmformation masks formed according to another embodiment of the presentinvention; and

FIG. 13 is an explanatory view showing a film formation mask formedaccording to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several preferred embodiments of the present invention will be describedin detail below with reference to the accompanying drawings. FIGS. 1 to4 are explanatory views showing a film formation mask according to oneembodiment of the present invention. A film formation mask 10 shown inthe drawings is used to form an organic layer having a predeterminedpattern, so that it is possible to form on substrate organic EL deviceseach including a pair of electrodes and an organic layer containing anorganic luminescent layer and interposed between the pair of electrodes.Here, so-called organic layer means a single or several organicluminescent layers. Alternatively, it means an organic luminescent layerand one or all of organic layers provided in the vicinity of the organicluminescent layer.

As shown in FIG. 1, a plurality of lower electrodes 2 consisting of ITOor the like are formed in accordance with a predetermined electrodestructure (for example, stripe-shaped electrodes) on a substrate 1consisting of a transparent glass, and a plurality of luminescent areaformation sections 3R, 3G, and 3B are formed and partitioned by virtueof an insulating film 3 over the lower electrodes. Then, a filmformation mask 10 is used to form a film pattern of an organic layerwhich contains a luminescent layer, in a manner such that theseluminescent area formation sections 3R, 3G, and 3B are covered up. In anembodiment shown in the accompanying drawings, red luminescent areaformation sections 3R, green luminescent area formation sections 3G, andblue luminescent area formation sections 3B are formed on each row. Infact, the film formation mask 10 is used to form a film pattern forforming luminescent areas corresponding to the luminescent areaformation sections of one of the three colors, and has a plurality ofopenings 10A according to the film pattern.

The film formation mask 10 used in the present embodiment has two falseopenings 10D, with one on each side of the mask and located outside thearea containing the openings 10A, which are not used in forming anorganic layer for forming luminescent areas. Such false openings 10Dwill be located on the substrate 1 outside the display area E of displaypanel, thereby forming organic layer false patterns 20 inside anadhesive applying area F. Here, so-called false patterns 20 are filmpatterns not involving luminescent areas, although they are patternsformed by the same material as the organic layer forming luminescentareas.

FIG. 2 is a plan view showing the film formation mask 10. As describedabove, the film formation mask 10 has the openings 10A and the falseopenings 10D. When the film formation mask 10 is disposed on a substratefor forming organic EL devices, the openings 10A of the film formationmask 10 are located inside the display area E of display panel, whilethe false openings 10D are placed outside the display area E. Althoughan example shown in FIG. 2 illustrates that the false openings 10D areprovided on both sides (left and right) of the area containing theopenings 10A, it is also possible for only one side (left or right) ofthe area (containing the openings 10A) to have such a false opening.

Actually, the film formation mask 10 of the present embodiment is suchthat its stripe-like openings 10A are formed in accordance with apredetermined pitch P. Where the openings 10A are used for painting twoor more different luminescent colors on organic luminescent layer, thepitch P is set at P=nP_(E) (n: number of different colors; P_(E):luminescent area pitch). Further, the width W of each opening 10A is setto be larger than the width of each luminescent area formation section(3R, 3G, 3B) mentioned above. Moreover, in the film formation processusing vapor deposition, there will be some film formation errors due tosome error factors (such as pattern deformation due to spread of vapordeposition flow, an operation deviation with the film formation mask, anerror of precision in forming mask openings). Accordingly, by making thewidth W to be larger than the width of each luminescent area formationsection, it is possible for film pattern not to deviate from theluminescent area formation sections even if it is expected that therewill be a maximum error in film formation.

The film formation mask 10 in the present embodiment has two falseopenings 10D separated by pitch P from the outermost openings 10A of themask 10. The width Wd of each false opening 10D is narrower than thewidth W of each opening 10A. In this way, when the film formation mask10 is slid by a distance P/n each time to form a false pattern 20 byvirtue of a false opening 10D, the formed false pattern 20 will not beoverlapped by film pattern. In determining the width Wd, it is necessaryto take into account some film formation errors based on some errorfactors (such as pattern deformation due to spread of vapor depositionflow, an operation deviation with the film formation mask, an error ofprecision in forming mask openings) Namely, if the above film formationerrors are taken into account while at the same time making the Wd ofeach false opening 10D to be narrower than the width W of each opening10A, it is possible to form the false patterns 20 without anyoverlapping.

FIG. 3 shows the dimension of the false openings 10D of the filmformation mask 10. As shown, the false openings 10D are to be located onthe substrate 1 outside the display area E to form the false patterns 20of an organic layer inside the adhesive applying area F, so that it isnecessary to take into account a relationship between the length of thefalse openings 10D and the inner edge F_(°) of the adhesive applyingarea F. In the present embodiment, the length of each false opening 10Dis shorter than the length of each opening 10A by ΔL, corresponding toeach corner portion of the substrate 1. In this way, it is possible toensure sufficient adhesive applying area F, and to avoid an overlapbetween the adhesive applying area F and the false patterns 20 formed byvirtue of the false openings 10D.

FIG. 4 is an explanatory view showing the function of the film formationmask 10 of the present embodiment. In practice, the film formation mask10 is disposed on the substrate 1 for forming a film pattern which laterforms luminescent areas on the substrate 1. At this time, a tension T isapplied to the edge portions of the mask so that the film formation mask10 will not become slack. Further, in the film formation mask 10 of thepresent embodiment, the false openings 10D formed beyond the outmostopenings 10A can absorb a deformation caused by the tension T, so thatthe width of each false opening 10D becomes larger (Wd<Wdt). In thisway, even if there is such tension T, there would be no change in thewidth W of each opening 10A which forms the film pattern on luminescentareas. Therefore, it is possible for an organic EL panel (formed by thefilm formation mask 10) to obtain a good display performance throughoutthe entire display area, without any disorder in film pattern near theoutermost edges of the display area.

FIG. 5 provides several explanatory views showing a method ofmanufacturing an organic EL panel using the film formation mask 10. Infact, an organic EL panel is formed by arranging a plurality of (orsingular number of) luminescent areas of organic EL devices as surfacelight emitting areas on a substrate. Although the following descriptionis focused on using the film formation mask 10 to paint an organicluminescent layer with different colors corresponding to respectiveluminescent colors, the description should not for many limitation tothe organic EL panel manufacturing method using the film formation mask10 of the present invention. In fact, the method of the presentinvention can also be applied to the case in which a film pattern of anorganic layer other than an organic luminescent layer is formedcorresponding to luminescent areas of various colors (for example, whencontrolling film thickness corresponding to different luminescentcolors). Further, although the following description is focused on filmformation by painting three colors (R, G, B), this description shouldnot for many limitation to the method of the present invention.Actually, the method of the present invention can also be applied to thecase in which film formation is effected by painting different colors toform luminescent areas of at least two colors, and to the case in whichfilm formation is effected by painting single one color through severaloperations.

FIG. 5A shows a process of forming film stripes 30R of a first color(red). Here, as shown in FIG. 1, the lower electrodes 2 and theinsulating film 3 are patterned on the substrate 1 by means ofphotolithography method or the like, thereby forming luminescent areas40R, 40G, and 40B partitioned by the insulating film 3. If necessary, anorganic layer (such as a hole-injection layer and a hole transportinglayer or the like) is formed to act as a substrate layer for an organicluminescent layer. Then, the openings 10A of the film formation mask 10are set corresponding to the luminescent areas 40R, and film stripes 30Rof the organic luminescent layer of the first color (red) are formed onthe luminescent areas 40R. At this time, since the film formation mask10 is provided with the false openings 10D, false patterns 20Rconsisting of the same organic luminescent layer are formed on thesubstrate 1 outside the region containing the luminescent areas.

FIG. 5B and FIG. 5C show processes of forming film stripes 30G of asecond color (green) and film stripes 30B of a third color (blue). Ineach of these processes, the film formation mask 10 is moved by adistance P/3, forming film stripes 30G of organic luminescent layer ofthe second color on luminescent areas 40G and film stripes 30B oforganic luminescent layer of the third color on luminescent areas 40B.Meanwhile, false patterns 20G and 20B consisting of the same organicluminescent material are formed on the substrate 1 outside the regioncontaining the luminescent areas.

Then, after other organic layers are formed thereon (if necessary),upper electrodes are formed in positions. Subsequently, as shown in FIG.5D, an adhesive agent 6 is applied to the perimeter of the substrate totightly bond an encapsulating member.

FIG. 6 is an explanatory view (a cross sectional view showing a portionnear the base end of the substrate) which illustrates an organic ELpanel according to an embodiment of the present invention. As shown, inthe organic EL panel of the invention, a plurality of lower electrodes 2are patterned on the substrate 1, an insulating film 3 is patterned onthe lower electrodes 2 in a manner such that luminescent areas 40R, 40G,and 40B (to be formed) are partitioned, an organic layer 4 is laminatedon the luminescent areas 40R, 40G and 40B, a plurality of upperelectrodes 5 are laminated on the organic layer 4. In this way, each oforganic EL devices formed on the substrate corresponding to therespective luminescent areas 40R, 40G and 40B has a structure in whichthe organic layer 4 is interposed between a pair of electrodes includinga lower electrode 2 and an upper electrode 5. Here, the substrate 1 is atransparent substrate, each lower electrode is a transparent electrodesuch as ITO electrode, thereby making it possible to obtain an organicEL panel (bottom emission type) which allows light to be taken out fromthe substrate 1 side. However, the present invention should not belimited by this type of EL panel. In fact, it is also possible to forman organic EL panel (top emission type) in which upper electrodes 5 aretransparent electrodes and light is taken from a side opposite to thesubstrate 1.

The organic layer 4 contains a hole injection layer 41 and a holetransporting layer 42 in a manner such that they cover up the entiredisplay area E. Further, the film formation mask 10 is used to form aluminescent layer 43 (serving as an organic luminescent layer) and anelectron transporting layer 44. Namely, the film stripes 30R, 30G, and30B of the luminescent layer 43 and the electron transporting layer 44are formed having a width corresponding to the width W of the openings10A of the film formation mask 10. In the embodiment shown in FIG. 6,the film stripes 30R, 30G, and 30B are continuously formed by thesetting of the width W of the openings 10A. Alternatively, the width Wis set in a manner such that the film stripes are formed with their edgeportions overlapped with each other or the film stripes are formed atrelatively large interval from one another. In the illustratedembodiment, the electron injection layer 45 is uniformly formed on thesefilm stripes 30R, 30G, and 30B.

Then, the false patterns 20R, 20G, and 20B are formed outside thedisplay area E on the substrate 1. Here, since the film formation mask10 is used to form the luminescent layer 43 and the electrontransporting layer 44, the false patterns 20R, 20G, and 20B are formedby virtue of the patterns 21R, 21G, and 21B obtained during theformation of the luminescent layer 43, as well as the patterns 22R, 22G,and 23B obtained during the formation of the electron transporting layer44. Further, an adhesive agent 6 is applied outside the outermost falsepatterns 20R, so that an adhesion surface 7 a of a cover 7 is allowed tobe pressed thereon, thereby rendering the cover 7 to be tightly bondedto the outer periphery of the substrate 1.

As described above, the organic layer 4 has a five-layer structureincluding the hole injection layer 41, the hole transporting layer 42,the luminescent layer 43, the electron transporting layer 44, and theelectron injection layer 45. On the other hand, it is also possible toform one-layer structure through four-layer structure by omitting (ifnecessary) some layers other than luminescent layer 43. Moreover, eachof the above layers can be produced not only in the form of singlelayer, but also possible to be in a multi-layer structure. Besides, itis allowable to add other organic layers (a hole barrier layer, anelectron barrier layer or the like).

Although the present embodiment shows that the film formation mask 10 isused to paint the luminescent layer 43 and the electron transportinglayer 44 with different colors, the film formation mask 10 can also beused to paint other organic layers with different colors. At this time,the false patterns of the organic layer material (to be painted withdifferent colors) are formed outside the display area E.

FIG. 7 is an explanatory view showing a method of manufacturing theorganic EL panel and the operation of the organic EL panel, inaccordance with the present embodiment. As shown, since the falsepatterns 20R, 20G, and 20B are formed outside the display area E, theydo not affect the display of the organic EL panel. Furthermore, sincethe false patterns 20R, 20G, and 20B are disposed in positions separatedfrom the film stripes 30R, 30G, and 30B forming the luminescent areas40R, 40G, and 40B, these false patterns can act as protective barriersfor preventing the adhesive agent 6 from getting into contact with areasnear the outermost film stripes 30R, 30G, and 30B.

On the other hand, the adhesive agent 6 generates moisture, oxygen gasor the like which are considered as factors deteriorating the organicluminescent layer. However, since moisture, oxygen gas or the like willerode through some transfer mediums in contact with each other, such anerosion can be prevented if the transfer mediums are not in contact witheach other. Namely, if the false patterns 20R, 20G, and 20B serving asprotection barriers for preventing the adhesive agent 6 from movingtowards the display area are located separately from areas near theoutermost film stripes 30R, 30G, and 30B, and if the false patterns 20R,20G, and 20B are made independent from one another, it is possible toprevent the areas near the outermost film stripes 30R, 30G, and 30B fromgetting eroded by the adhesive agent.

In order to obtain the above-mentioned effect, it is necessary for thefalse patterns 20R, 20G, and 20B to be sized such that they are not indirect connection with the areas near the outermost film stripes 30R,30G, and 30B. On the other hand, the false patterns 20R, 20G, and 20Bshould not be separated too far away from the display area E, since suchan arrangement can reduce a desired utilization efficiency (displayarea/panel area) of display panel. For this reason, it is required thatthe false patterns be formed in positions separated from the outermostfilm stripes 30R, 30G, and 30B at the same pitch as the film stripes.Further, where such separation has been set smaller than the pitch ofthe film stripes, it is preferable that the width Wd of false openingsbe made small. If the width W1 of the film stripes 30R, 30G, and 30B islarger than P/3, the edge portions of the film stripes 30R, 30G, and 30Bwill be overlapped with each other. Accordingly, to independentlyarrange the false patterns 20R, 20G, 20B with an interval S, it isnecessary for the Wd1 of the false patterns 20R, 20G, and 20B to besmaller than the width W1 of the film stripes 30R, 30G, and 30B.

Therefore, as mentioned above, the width Wd of the false openings 10D ofthe film formation mask 10 is set to be smaller than the width W of theopenings 10A. On the other hand, although the width Wd1 of the falsepatterns 20R, 20G, and 20B is determined by the width Wd of the falseopenings 10D, the width Wd1 of the false patterns will not be exactlyequal to the width Wd of the false openings 10D. This is because theremay be some film formation errors due to some error factors (such aspattern deformation due to spread of vapor deposition flow, an operationdeviation with the film formation mask, an error of precision in formingmask openings). In view of this, the Wd width of the false openings 10Dshould be set such that the false patterns 20R, 20G, and 20B will not beoverlapped with each other (to ensure the formation of the interval S).

The above-described embodiment shows that in the process ofmanufacturing an organic EL panel, the film formation mask 10 is causedto slide only a distance P/n (P: pitch of openings 10A; n: the number ofdifferent colors for painting) so as to form n lengths of falsepatterns. However, such an embodiment should not form any limitation tothe present invention. For example, FIG. 8 is an explanatory viewshowing a film formation mask formed according to another embodiment ofthe present invention.

In this embodiment, as shown in FIGS. 8A to 8C, a plurality of paintingswith different colors are performed by different film formation masks11(R), 11(G), and 11(B). In each of the film formation masks 11(R),11(G), and 11(B), a plurality of openings 11A corresponding to the filmstripes which form luminescent areas in various film formation processesare formed with the same pitch P as the above-described embodiment.Then, outside the outermost openings 11A on the film formation masks11(R), 11(G), and 11(B), there are formed false openings 11D separatedP1, P2, and P3 (P2=P1+P/3, P3=P2+P/3) from the outermost openings 11A ofthe film formation masks 11(R), 11(G), and 11(B).

FIG. 9 is an explanatory view showing an organic EL panel painted bydifferent colors in different luminescent areas using film formationmasks 11(R), 11(G), and 11(B). Actually, in the process of forming thefilm stripes 30R, 30G, and 30B, patterns based on the false openings 11Dare laminated in positions separated P1, P2, and P3 from the filmstripes 30R, 30G, and 30B, so that it is possible to form one falsepattern 21 in each area. In this way, since it is possible to increasethe height of each laminated false pattern 21, it is allowed to increasean effect of blocking an adhesive agent. Further, since the falsepattern 21 is required to be formed in only one position, it is allowedto increase the space efficiency of the panel.

In the embodiment shown in FIG. 8, the film formation masks 11(R),11(G), and 11(B) can also be constructed such that the false openings11D are formed on both sides of each mask, or that only one falseopening is formed on only one side of each mask. Moreover, it is notabsolutely necessary for each of the three film formation masks 11(R),11(G), and 11(B) to be formed with false opening(s) 11D. In fact, it isallowable to select only one or two of the masks to have such falseopening(s) 11D. Alternatively, among the film formation masks 11(R),11(G), and 11(B), one of them is formed on one side thereof with a falseopening 11D, while another is formed on the other side thereof with afalse opening 11D.

FIGS. 10A-10C are explanatory views showing an example of a falsepattern 22 formed in one position. By shaping the false opening 11D intoan appropriate form, it is allowed to form a false pattern 22corresponding in shape to the false opening 11D. FIG. 10A shows that inan area near an edge of the substrate, the length of the false pattern22 is ΔL shorter than the film stripe 30R (30G, 30B). FIG. 10B showsthat in an area near an edge of the substrate, the length of the falsepattern 22 is ΔL longer than the film stripe 30R (30G, 30B) to ensure animproved effect of blocking an adhesive agent. FIG. 10C shows that thefalse pattern 22 (22A, 22B . . . ) can be divided into several portionsso as to form false patterns (of expensive organic material) only innecessary areas.

Other embodiments of the film formation mask will be described belowwith reference to FIGS. 11-13. FIG. 11A is a plan view and FIG. 11B isan enlarged view showing in detail a portion (portion A) of FIG. 11A. Anembodiment shown in FIGS. 11A and 11B is a film formation mask for usein forming a plurality of panels on a large-sized substrate. As shown inFIG. 11A, a large-scaled film formation mask 12 includes a plurality ofmask units M each corresponding to one piece of panel. Each mask unit Mincludes a plurality of openings 12A and the false openings 12D arrangedin the same manner as that shown in FIG. 2. Further, as shown in FIG.11A, the plurality of mask units M are arranged in both longitudinal andlateral directions. Specifically, it is important to prevent a slackingwhen the large-sized film formation mask 12 is being set in positionduring a manufacturing process, so that a relatively large tension T isadded. At this time, as shown in FIG. 11B, since a possible deformationcaused by the tension T can be absorbed by the false openings 12Dlocated near the outer edges of each mask unit M, there would be nodeformation in the openings 12A for forming luminescent areas. In thisway, with regard to each panel, it is possible to form film stripes withhigh precision in an entire display area, thereby obtaining panels withhigh display performance.

Although the film formation masks 10, 11, and 12 in the above-describedembodiments have stripe-like openings 10A, 11A, and 12A, the openings offilm formation masks of the present invention should not be limited tostripe-like shape. For example, FIGS. 12A-12C show film formation masksformed according to further embodiments of the present invention. FIG.12A shows a film formation mask 13 having vertically (in the drawing)arranged rectangular openings 13A disposed alternately corresponding tothe display area E, while false openings 13D having the same shape asthe openings 13A are formed as extensions of the arrangement of theopenings 13A on the outside of the display area E. FIG. 12B shows a filmformation mask 14 having vertically (in the drawing) arrangedrectangular openings 14A disposed alternately corresponding to thedisplay area E, while only a single one false opening 14D having anelongated shape is formed on the outside of the display area E. FIG. 12Cshows a film formation mask 15 having horizontally (in the drawing)arranged rectangular openings 15A disposed alternately corresponding tothe display area E, while false openings 15D having the same shape asthe openings 15A are formed corresponding to all horizontal rows of theopenings 15A on the outside of the display area E, thereby forming acolumn of the false openings 15D.

Actually, the shape of the false openings should not be specificallylimited, but can be in any one of other forms, provided that it ispossible to ensure an effect of absorbing a distortion during anaddition of a tension, as well as to form false patterns outside thedisplay area for acting as adhesive blocking barriers.

Although the above embodiments have been described on the assumptionthat different colors are painted on the formed films divided inaccordance with respective luminescent colors, the present inventionshould not be limited by these embodiments. In particular, as a methodof forming color display panel, it is allowed to employ not only themethod of painting different colors (two or more colors) on aluminescent layer by sliding or changing a film formation mask, but alsoCF Method or CCM Method which combines a color conversion layer (basedon a color filter or fluorescent material) with a luminescent layer of asingle color such as white or blue, as well as Photobleaching Methodwhich applies an electromagnetic wave or the like to the luminescentareas of monochromatic luminescent layer so as to realize a plurality ofluminescent layers. Further, as color display panel formation method notinvolving painting different colors, it is allowed to carry out aprocess which does not involve repeatedly using the film formation mask.

For example, it is possible to use a film formation mask 16 shown inFIG. 13. As shown, the film formation mask 16 has an opening 16Acorresponding to the display area E, as well as a false opening 16Dformed outside the outermost edge of the opening 16A and not involved informing organic layer in luminescent area. In this way, when a filmpattern of an organic layer is formed all over the display area E, it ispossible to form a false pattern of an organic layer on the outside ofthe display area E. Therefore, no matter which of the aforementioned CFMethod, CCM Method and Photobleaching Method is employed, it is possibleto form the false pattern functioning as a protection barrier (forblocking an adhesive agent) on the outside of the display area.

Moreover, film formation mask, organic EL panel, and organic EL panelmanufacturing method should not be limited by the structure of organicEL devices, and in fact it is possible to laminate a plurality oforganic luminescent layers (each interposed between a pair ofelectrodes) on the substrate so as to form a multi-color luminescentstructure. For example, it is possible to laminate (on the substrate)lower electrodes, a first organic luminescent layer, first intermediateelectrodes, a second organic luminescent layer, second intermediateelectrodes, a third organic luminescent layer, and upper electrodes.

The features and advantages of film formation mask, organic EL panel,and organic EL panel manufacturing method according to the preferredembodiments of the present invention may be concluded as follows.

Firstly, the film formation mask of the present invention has openingsarranged corresponding to a film pattern for forming luminescent areasof the organic EL devices, and has false openings located outside anarea containing the openings. Therefore, a tension added when settingthe film formation mask can be absorbed by the false openings, therebypreventing an undesired deformation of the openings formed correspondingto luminescent areas. As a result, there would be no film patterndisorder near the outermost edge of the display area.

Secondly, film pattern of an organic layer for forming luminescent areasof organic EL devices are formed on the substrate by virtue of theopenings of the film formation mask, while the false patterns of theorganic layer are formed outside an area containing luminescent areas,by virtue of the false openings. In this way, the false patterns canserve as protection barrier for blocking an adhesive agent appliedaround the display area, thereby preventing the outmost edge of thedisplay area from contacting the adhesive agent, thus preventing anerosion of the adhesive into the display area.

Thirdly, using the method of manufacturing an organic EL panel, thefalse patterns serving as protection barrier for blocking an adhesiveagent and the film pattern for forming luminescent areas can be formedsimultaneously. Therefore, it is possible to realize an efficientformation of the false patterns without having to change the existingmanufacturing process.

Fourthly, with regard to the above-described film formation mask, theorganic EL panel, and the method of manufacturing the organic EL panel,since the width of each false opening is set to be narrower than thewidth of each opening, and since the width of each false pattern is setto be narrower than the width of each film stripe for formingluminescent areas, even if the film formation mask is slid a distanceequal to the width of an opening in order to paint different colors onthe film pattern, it is still possible for the false patterns to beformed completely separated from film pattern. In this way, by virtue ofthe separately formed false patterns, it is possible to protect theluminescent areas by completely blocking some deterioration factors(harmful to the organic layer) transported inwardly through the contactwith the adhesive agent, thereby exactly enabling the false patterns toact as barriers for blocking the adhesive agent.

Fifthly, since film formation error in forming patterns is taken intoaccount when setting the width of the false openings and the width ofthe false patterns, it is possible to exactly separate the falsepatterns (even if film formation errors have occurred due to variouserror factors) from film pattern. Consequently, by virtue of theseparately formed false patterns, it is possible to protect theluminescent areas by completely blocking some deterioration factors(harmful to the organic layer) transported inwardly through the contactwith the adhesive agent, thereby exactly enabling the false patterns toact as barriers for blocking the adhesive agent.

Sixthly, with the above-described film formation mask, organic EL paneland organic EL panel manufacturing method, since the length of the falseopenings is shorter than the length of the above openings in the cornerportions of the substrate, and since the length of the false openings isshorter than the length of a film pattern, there would be no overlapbetween an adhesive area and a false pattern (even if an adhesive areahas been made quite large in a corner of the substrate), therebyensuring an exact bonding of a cover and enabling the false patterns tofunction as protective barriers.

Seventhly, with the above-described film formation mask, organic ELpanel and organic EL panel manufacturing method, since the openings ofthe film formation mask are used to paint at least two luminescentcolors on the organic luminescent layer, and since the film pattern isformed by painting different colors, it is possible to form a pluralityof false patterns by virtue of the false openings, corresponding to thenumber of times of painting different colors. In this way, a pluralityof false patterns may be formed simultaneously in the process ofpainting different colors in luminescent areas. Moreover, it is possiblefor a plurality of false patterns to exactly protect the organic layerfrom several factors (harmful to the organic layer) transported from theadhesive agent.

EXAMPLE

An example of the present invention will be described in the following.However, the present invention should not be limited by such specificexample.

[Film Formation Mask]

The film formation mask is formed by processing a metal film containingnickel or the like, by virtue of chemical etching, mechanical polishing,or sandblasting. On the other hand, it is also possible to employ anelectro-casting method which is excellent informing a fine pattern witha high precision and adapted to form thick mask portion in a filmformation mask.

When electro-casting method is used, at first, a patterning resist isformed by photolithography process on a metal electro-casting matrix. Indetail, the patterning resist is formed corresponding to the openingpattern and false opening pattern of the film formation mask. Then,after depositing a film formation mask material on the electro-castingmatrix in an electrolytic solution and thus forming mask portion, themask portion having formed thereon a desired opening pattern and adesired false opening pattern can be produced by removing the patterningresist. At this time, an appropriately completed film formation mask canbe obtained by removing the mask portion from the electro-castingmatrix.

The sizes of various parts of the film formation mask are as shown inFIG. 2 (where three different colors are painted) Namely, if the width Wof the openings is W=50 μm, the pitch P of the openings will be P≦3×50μm. Moreover, since there are some error factors including deformationamount e1 (an arrival error of vapor deposition flow) due to an intervalbetween the film formation mask and the substrate, an operationdeviation amount e2 occurred when setting the film formation mask on thesubstrate, and an error amount e3 in mask pattern formation precision,the width Wd of the false openings should be set to be narrower than thewidth W of the openings. That is, the width Wd of each false opening isset by Wd=W−(e1+e2+e3), so that when W=50 μm and when e1=e2=e3=5 μm, thewidth Wd of each false opening will be Wd=35 μm.

[Organic EL panel]

Various portions of an organic EL panel are shown in the following Table1.

TABLE 1 Components Suitable Materials Functions Substrate Glass DisplaySubstrate (Bottom Emission) Lower ITO, IZO, In₂O₃ Anodes (TransparentElectrodes Electrodes) Insulating Polyimide Layer Hole Injection CuPcOrganic Layer Layer Hole NBP, PPD, m-MTDATA Organic Transporting LayerLayer Luminescent Alq₃ + DCM Organic Luminescent Layers (R) Alq₃ +Coumarin Layer (G) IDE120 + IDE102 (B) BAIq + Perylene Electron AIq₃,OXD-1 Organic Layer Transporting Layer Electron LiO₂, LiF Organic LayerInjection Layer Upper Al, Mg, Mg—Ag Cathodes Electrodes Adhesive AgentUV-Curable Resin Cover Glass, Metal Cap[Manufacturing Method]

An electrode material for forming anodes is deposited as a thin film ona substrate by virtue of vapor deposition, sputtering or the like,followed by patterning the deposited film into a desired electrodestructure by photolithography process or the like. Further, aninsulating material is applied and luminescent area formation portionsare patterned by photolithography process or the like. Subsequently,hole injection layer material and hole transporting layer material arevapor deposited successively.

Next, film formation mask is used to deposit luminescent-layer materialin accordance with RGB luminescent areas, thereby forming a desired filmpattern in the display area of a display panel. Meanwhile, falsepatterns consisting of luminescent-layer material are formed outside thedisplay area. Afterwards, electron transporting-layer material andelectron-injection layer material are vapor-deposited successively onthe formed film pattern in the display area, followed byvapor-depositing an electrode material for forming upper electrodes.

Then, an adhesive agent is applied to the outermost edge of the formeddisplay area and to the outside of false patterns. Subsequently, theadhesion surface of a cover is pressed to the adhesive-applied area, soas to tightly bond the cover (covering the display area and the falsepatterns) to the substrate.

While there has been described what are at present considered to bepreferred embodiments of the present invention, it will be understoodthat various modifications may be made thereto, and it is intended thatthe appended claims cover all such modifications as fall within the truespirit and scope of the invention.

1. An organic EL panel including a substrate and organic EL devicesformed on the substrate, each organic EL device including a pair ofelectrodes and an organic layer containing an organic luminescent layer,said organic layer being interposed between the pair of electrodes,wherein formed on the substrate are a film pattern of the organic layerfor forming luminescent areas of the organic EL devices, and falsepatterns of the organic layer located outside an area containing theluminescent areas, wherein the width of each false pattern is smallerthan the width of each film stripe.
 2. The organic EL panel according toclaim 1, wherein the false patterns are formed by virtue of the falseopenings of a film formation mask which has openings for forming thefilm pattern, said false openings being located outside an areacontaining said openings.
 3. The organic EL panel according to claim 1,wherein the length of each false pattern is shorter than the length ofeach film stripe in the corner portions of the substrate.
 4. The organicEL panel according to claim 1, wherein said film pattern is formed bypainting two or more different luminescent colors on the organicluminescent layer.
 5. An organic EL panel including a substrate andorganic EL devices formed on the substrate, each organic EL deviceincluding a pair of electrodes and an organic layer containing anorganic luminescent layer, said organic layer being interposed betweenthe pair of electrodes, wherein formed on the substrate are a filmpattern of the organic layer for forming luminescent areas of theorganic EL devices, and false patterns of the organic layer locatedoutside an area containing the luminescent areas, wherein the length ofeach false pattern is shorter than the length of each film stripe in thecorner portions of the substrate.
 6. The organic EL panel according toclaim 5, wherein the false patterns are formed by virtue of the falseopenings of a film formation mask which has openings for forming thefilm pattern, said false openings being located outside an areacontaining said openings.
 7. The organic EL panel according to claim 5,wherein the width of each false pattern is smaller than the width ofeach film stripe.
 8. The organic EL panel according to claim 5, whereinsaid film pattern is formed by painting two or more differentluminescent colors on the organic luminescent layer.